JP2009175046A - Processing device and producing method of thin-film sample - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a processing device of a processing sample for allowing high speed and accurate etching, and to provide a production method of thin-film samples. <P>SOLUTION: This processing device includes a holder 50, an ion gun 20, and an electron gun 10. The holder 50 has a front surface and a back surface, substantially inparallel with each other, and grips the processing sample having a thickness defined as the distance of the front surface and back surface. The ion gun 20 emits argon ions and irradiates argon ions to the back surface of the processing sample gripped by the holder 50. The electron gun 10 emits electrons and is constituted so as to irradiate the electrons to the front surface of the processing sample gripped by the holder 50. A microcomputer 30 controls the current density of the argon ions emitted by the ion gun 20, based on the current density of transmitted electrons measured by a current detector 40. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a processing apparatus for thinning a workpiece and a method for producing a thin film sample. In particular, it relates to an apparatus and method for producing a thin film sample for a transmission electron microscope.

  Conventionally, as a processing apparatus for producing a thin film sample for a transmission electron microscope (hereinafter referred to as TEM (Transmission Electron Microscope)), a sample to be processed (hereinafter referred to as a processed sample) is processed by irradiation with an ion beam. In this case, it is known that electrons are also irradiated onto a processed sample. This type of conventional apparatus is configured to estimate the thickness of a processed sample by irradiating electrons parallel to the thickness direction of the processed sample and measuring the amount of transmitted electrons that increase as the processed sample becomes thinner. Has been. That is, in this type of apparatus, it is possible to know the progress of processing by the above estimation (see, for example, Patent Document 1).

In addition, as a conventional apparatus, a processing apparatus that irradiates a processed sample with electrons as well as Patent Document 1 when an insulating processed sample is processed by ion beam irradiation is known.
If an insulating processed sample is irradiated with only cations by an ion gun and the processed sample is etched, the processed sample is positively charged by the cations, and the cations and processed sample are electrically repelled. As a result, the efficiency of etching deteriorates, and the time required for etching increases.

  Therefore, this processing apparatus is configured so as to prevent the etching efficiency from being deteriorated by irradiating the processing sample with electrons by an electron gun to neutralize the charging. At the same time, the laser beam is transmitted through the processed sample, and the processing is performed while confirming whether the processed sample can be observed by TEM by observing the transmitted light of the laser (for example, see Patent Document 2). .

On the other hand, as processing apparatuses other than those for the purpose of preparing a thin film sample for TEM observation, apparatuses that process an object to be processed with electrically neutral atoms are known (for example, see Non-Patent Documents 1 and 2). ). Electrically neutral atoms are called atomic beams. In addition, irradiation with atomic beams is called atomic beam irradiation. According to the processing technique using atomic beam irradiation described in the above document, although the etching rate is slow, the processing finish can be made clean. Therefore, according to this technique, precise etching is possible.
JP-A-8-5528 JP 11-132920 A Michihiko Suhara, 3 others, “Characterization of Argon Fast Atom Beam Source and Application to Mesa Etching Process for GaInP / GaAs Triple-Barrier Resonant Tunneling Diodes), Japanese Journal of Applied Physics, 2006, 45, 6B, p.5504-5508 Yasushi Toma, 6 others, “Fast Atom Beam Etching of Glass Materials with Contact and Non-Contact Masks”, Japanese Journal of Applied Physics (Japanese Journal of Applied Physics), 1997, Volume 36, 12B, p.7655-7659

  However, the techniques described in Patent Documents 1 and 2 have a problem that rapid etching cannot be realized by cations. The reason is that the cations and electrons are irradiated on the same surface of the processed sample. Therefore, before the cations are irradiated on the processed sample, the cations and electrons combine to become electrically neutral atoms. Because it ends up. That is, in the techniques described in Patent Documents 1 and 2, since the cation is replaced with an atom by the reaction between the cation and the electron, the etching efficiency is poor.

  State another issue. As described above, in the finishing step, it is desirable to perform processing by atomic beam irradiation. This is because although the etching rate is slow, the processing is finished cleanly. However, according to the techniques of Patent Documents 1 and 2, it is impossible to control how much the released cation changes to an electrically neutral atom. Therefore, it is fully conceivable that cations are irradiated to the processed sample at the finishing stage. That is, with the techniques described in Patent Documents 1 and 2, it has been difficult to finish the processing cleanly.

  Further, since the techniques described in Non-Patent Documents 1 and 2 are etching techniques based on atomic beam irradiation, high-precision etching can be realized based on this technique. However, there is a problem that the etching efficiency is low at the initial stage of processing. That is, in the techniques described in Non-Patent Documents 1 and 2, although the object to be processed can be processed with high accuracy, the processing efficiency by etching before the finishing stage is poor, and as a result, the processing process takes time. there were.

For the reasons described above, in the prior art, the time from the start of processing to the start of observation by TEM is long, and the user needs a lot of time and labor.
The present invention has been made in view of these problems, and an object of the present invention is to provide a processing apparatus and a method for producing a thin film sample that can thin a workpiece to be processed at high speed and high accuracy.

  The processing apparatus according to claim 1, which has been made to achieve such an object, includes a holder, an ion gun, and an electron gun. The holder grips the workpiece. The ion gun emits predetermined cations and irradiates the processing object held by the holder with cations. The electron gun emits electrons and irradiates the processing object held by the holder with electrons. In this manner, this processing apparatus reduces the thickness, which is the distance between the front surface and the back surface of the processing object held by the holder.

  The electron gun is disposed so as to be able to irradiate electrons on the surface of the workpiece. Further, the ion gun is disposed so that the back surface of the workpiece can be irradiated with cations. In this manner, the processing apparatus is configured to irradiate the back surface of the processing target object with the cations, irradiate the surface of the processing target object with electrons, and reduce the thickness of the processing target object held by the holder. Has been.

  According to the processing apparatus configured as described above, the combination of ions and electrons does not occur unless the ions or electrons pass through the object to be processed. In other words, in a state where the workpiece is thick and hardly transmits electrons, ions and electrons are hardly combined. Therefore, in this state, highly efficient etching with ions becomes possible.

  On the other hand, in a state where the thinning of the workpiece is progressing and a small number of electrons are transmitted through the workpiece, the electrons transmitted through the workpiece (hereinafter referred to as transmitted electrons) and ions are combined. Electrically neutral atoms are generated and atomic beam irradiation is performed.

  By the way, as described above, the atomic beam irradiation is an etching which is easy to control the etching and is suitable for the finishing process. That is, when the thinning of the object to be processed progresses and it is desirable to shift to the finishing process, the processing apparatus naturally shifts to low-efficiency etching. Therefore, according to this processing apparatus, the object to be processed can be thinned at high speed and with high accuracy.

  Therefore, if this processing apparatus is used as an apparatus for producing a thin film sample suitable for TEM observation, the thin film sample can be finished neatly and the time from processing to observation can be shortened.

  Further, the processing apparatus of claim 1 may be configured as described in claim 2. The processing apparatus of claim 2 includes a current detector and a controller in addition to the configuration of claim 1. The current detector measures the current density of electrons that are irradiated onto the surface of the workpiece by the electron gun and transmitted from the front surface to the back surface. The controller controls the current density of a predetermined cation emitted by the ion gun based on the measurement result of the current detector.

  In the first place, there is a negative correlation between the current density of transmitted electrons and the thickness of the workpiece. Therefore, according to the configuration of claim 2, it is possible to gradually shift from roughing to finishing by controlling so that the current density of ions emitted from the ion gun is reduced as the current density of the transmission current increases. It becomes.

  In addition, a holder that holds the object to be processed, a predetermined cation is released, an ion gun that irradiates the object to be processed held by the holder, an electron gun, and an electron that is released and held by the holder A processing apparatus that includes an electron gun that irradiates electrons to a processing object and that reduces the thickness, which is the distance between the front surface and the back surface of the processing object gripped by the holder, is emitted from the electron gun. It is preferable to provide an optical system that outputs, as image information, an image generated by electrons that have passed through the object to be processed.

Providing the optical system in this way can reduce the time and labor required from processing to observation and vice versa (claim 3).
For example, it is convenient that the thinned workpiece can be observed without transferring the thinned workpiece to another microscope and observing it. In addition, even though the thinned sample was determined to be suitable for observation by TEM by a laser or current detector, when actually observing this with TEM, the desired image could not be observed, It can be prevented from developing into a situation where processing is repeated.

  Moreover, the processing apparatus according to claim 3 may be configured as described in claim 4. According to a fourth aspect of the present invention, there is provided the processing apparatus according to the third aspect, wherein the electron gun is disposed so as to irradiate the surface of the object to be processed held by the holder, and the ion gun is further processed. The rear surface of the object is disposed so as to be able to irradiate a predetermined cation.

If comprised in this way, the effect which the processing apparatus described in Claim 1 show | plays can also be show | played also in the processing apparatus of Claim 4.
By the way, in the observation by TEM, it is desirable that the pressure is kept low in the space from when the electron is emitted until it is detected by the electron detector. However, if the ion gun emits ions, the pressure in the space naturally increases. In particular, the influence of the pressure increase near the electron gun and the electron detector on the observation is large.

  Therefore, the processing apparatus according to claim 3 or 4 may be configured as described in claim 5. A processing apparatus according to a fifth aspect includes a first shutter, an electronic detector, a second shutter, and a case in addition to the configuration according to the third or fourth aspect.

  The electron detector is configured to detect electrons irradiated from the front surface to the back surface by irradiating the surface of the workpiece with an electron gun, and constitutes the optical system. In addition, the case seals a space including an electron flight path from when it is emitted from the electron gun until it is detected by the electron detector so as not to allow atoms to pass therethrough.

  The first shutter is provided between the electron gun and the holder, and partitions the space in the case. In addition, the second shutter is provided between the holder and the electron detector, and partitions the space in the case. The first shutter and the second shutter are configured so as to transmit electrons emitted from the electron gun but not transmit atoms.

  According to the processing apparatus configured as described above, the phenomenon that the pressure increases in the process of processing can be kept near the object to be processed, and the pressure near the electron gun or the electron detector is The pressure suitable for observation can be maintained.

  In addition, the processing apparatus according to any one of claims 1 to 5 is configured to release a rare gas atom or a gallium atom ionized as a predetermined cation as described in claim 6. Good. That is, ions suitable for an ion gun can be used as in a conventional processing apparatus. If it does in this way, the processing apparatus of the present invention can be constituted at low cost.

  The processing apparatus according to claims 1 to 6 may be configured as in claim 7. In the processing apparatus according to the seventh aspect, the holder is configured to be able to rotate the gripped workpiece about the rotation axis parallel to the thickness direction of the gripped workpiece. According to the processing apparatus configured as described above, processing can be performed without unevenness, and finishing of the processing can be made more beautiful.

  The eighth aspect of the present invention relates to an invention of a method for producing a thin film sample. This method for producing a thin film sample is a production method for making a thin film by thinly processing a workpiece. Specifically, by irradiating the surface of the workpiece with electrons and irradiating a predetermined cation on the back surface symmetrically with the surface, the thickness of the workpiece as the distance between the front surface and the back surface Process so that becomes thin. Therefore, according to this production method, an effect equivalent to that of the invention of claim 1 can be obtained.

  According to a ninth aspect of the present invention, there is provided a method for producing a thin film sample, comprising: measuring a current density of electrons irradiated on a surface of a workpiece and transmitting from the front surface to the back surface; and releasing a predetermined cation based on the measurement result. The workpiece is processed by controlling the current density. Therefore, according to this production method, the same effect as that of the invention of claim 2 can be obtained.

  Further, claim 8 may specifically be the following method. Based on the measurement result of X, which is the value of the current density of electrons emitted from the front surface to the back surface, electrons are emitted at a constant current density S, and divided into a first step, a second step, and a third step. A thin film sample production method for controlling Y, which is a value of current density at the time of release of cations, wherein r, V, R, S and d are 0 <r <V <R ≦ S and R ≦ (U × d) is a positive constant, the first step is Y = U when X <r, the second step is Y = (U−X) when r ≦ X <V, and the third step The process is set to Y = (X * d) when V ≦ X <R, the third process is finished when R ≦ X, and the processing is finished with Y = 0.

  D may be a variable. And when measuring X, it is good to stop discharge | release of ion.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration of a processing apparatus 1 according to the present embodiment. The processing apparatus 1 includes a case 5, an electron gun 10, an ion gun 20, a microcomputer (hereinafter referred to as a microcomputer) 30, a current detector 40 and a holder 50.

  The processed sample is processed in advance so as to have a thickness of about several tens of μm, and is inserted into a metal ring. It is the role of the processing apparatus 1 to process this thickness to a thickness (about 100 nm) suitable for observation by TEM. Here, the surface that is orthogonal to the thickness direction of the processed sample and is processed by the processing apparatus 1 is referred to as a back surface. A surface that is orthogonal to the thickness direction of the processed sample and is not processed by the processing apparatus 1 is referred to as a surface. Moreover, the front surface and the back surface shall be previously processed circularly.

  From here, each component is demonstrated. First, the holder 50 is configured to be able to grip this processed sample. Specifically, the metal ring in which the processed sample is inserted is gripped from the outside. The holder 50 is configured to be able to rotate the processed sample while holding the processed sample. Since this rotating mechanism is provided in an existing processing apparatus, it will be briefly described with reference to FIG.

  FIG. 2A is a top view showing details of the rotation mechanism of the holder 50 described above. The holder 50 includes a motor 51, a belt 53, a gear 55, and a rotary stage 57. The motor 51 constantly rotates at a predetermined rotational speed and transmits the rotational motion to the belt 53. The belt 53 transmits the rotational motion to the gear 55. Then, the rotary stage that grips the processed sample engaged with the gear 55 rotates.

  FIG. 2B is a view showing an AA cross section of the rotary stage 57. The rotation stage 57 is configured so that the rotation axis coincides with the center of the processed sample. By processing while rotating the processed sample in this way, processing can be performed without unevenness, and the finish becomes beautiful.

  Returning to FIG. The electron gun 10 is a thermoelectron type used in a known ion milling apparatus or the like, and is arranged at a position where electrons can be irradiated onto the surface of a processed sample. Specifically, the electron gun 10 is provided so that the thickness direction of the processed sample and the traveling direction of the irradiated electrons are substantially parallel when the processed sample is held by the holder 50.

  The ion gun 20 is a well-known one used in a known ion milling apparatus or the like, and emits argon ions from a predetermined angle with respect to the back surface of the processed sample. Further, the current density of the released argon is configured to be controllable based on a command sent from the microcomputer 30.

  Further, the case 5 is configured to cover and seal the flight path of emitted electrons and argon ions. The pressure inside the case 5 is previously lowered. There are two purposes. One is to appropriately irradiate the processed sample with the electron beam emitted from the electron gun 10 and the argon emitted from the ion gun 20. The other is to allow the current detector 40 to capture transmitted electrons.

  The current detector 40 captures electrons irradiated from the electron gun and transmitted through the processed sample, and measures the current density of the captured electrons. Then, the information is transmitted to the microcomputer 30.

  The microcomputer 30 is a known one having a CPU, a ROM, a RAM, and the like. Based on the current density information sent from the current detector 40, the current density of argon ions emitted from the ion gun 20 is controlled. Details of this control will be described later with reference to FIG.

  From here, what phenomenon occurs in the process in which the thickness of the processed sample is processed thin by the processing apparatus 1 will be described with reference to FIG. Fig.3 (a) is the figure which looked at the whole process sample from the top, and FF (straight line which passes along the center of a circle) sectional drawing. Moreover, FIG.3 (b), FIG.3 (c), and FIG.3 (d) are the enlarged views of the center part vicinity of FF sectional drawing. Here, it is assumed that processing proceeds in order from FIG. 3B to FIG. 3C and FIG. 3D.

FIG. 3B shows a state when the processed sample is thick soon after the processing is started. Incidentally, the processed sample is processed in advance so that the back surface is recessed toward the center.
In this state, electrons can hardly pass through the processed sample. In other words, since argon ions and electrons are hardly combined to change into an atomic beam, atomic beam irradiation does not occur, and etching efficiency does not deteriorate as in the prior art.

  Further, even when the processed sample is an insulator, the processed sample and the argon ions are not electrically repelled because the processed sample is kept electrically neutral by the electrons irradiated on the surface. Incidentally, if the processed sample is a conductor, it will not be charged even if the surface is not irradiated with electrons.

  Then, as the processing progresses and the processed sample becomes thinner, the state as shown in FIG. In this state, the number of transmitted electrons gradually increases. However, when this state starts, the processed sample is thicker and needs to be processed thinner to observe with TEM.

  In this state, the transmitted electrons have two functions. One is to change argon ions into atomic beams by combining with argon ions. As described above, when this bond occurs, atomic beam irradiation occurs. Atomic beam irradiation can finish the process neatly, though the etching efficiency is poor.

  That is, when the processed sample is thick, high-efficiency etching, that is, rough processing is performed by argon ions. Then, when the thickness approaches a thickness suitable for TEM observation, a state of low-efficiency etching with atomic beams (atomic beam irradiation), that is, finish processing is naturally achieved.

  When the processing is further advanced, as shown in FIG. 3 (d), a hole is opened at the center of the processed sample. As described above, the processed sample is processed in advance so as to be recessed toward the center. Therefore, if a hole is made, a thickness suitable for observation by TEM can be found in the vicinity of the hole. Therefore, the processing is finished when the hole is opened. And let the processed sample of this state be a thin film sample.

  If finishing is performed by atomic beam irradiation in this way, several merits are obtained. For example, the thickness control accuracy is improved, damage to the processed sample can be reduced, and the thickness is uniformly finished. As described above, when it is desired to move from roughing to finishing, this is naturally an excellent effect of the present invention.

  Another function of the transmitted electrons is to be detected by the current detector 40. As described above, the current detector 40 captures the transmitted electrons, measures the current density, and sends the information to the microcomputer 30. The microcomputer 30 controls the current density of argon ions emitted from the ion gun 20 based on the information. Next, this control will be described with reference to FIG.

  FIG. 4 is a flowchart showing an ion gun control process executed mainly by a CPU included in the microcomputer 30. This process is divided into three steps based on the current density of electrons detected by the current detector 40 (hereinafter referred to as electron current density), and the current density of argon ions emitted by the ion gun 20 (hereinafter referred to as electron current density). (Referred to as argon current density).

  Prior to detailed description, an outline of the three steps will be described. The first step is rough processing, in which the argon current density is kept constant at a large value, and the processed sample is irradiated with argon ions. And a 2nd process is a process performed in the transition stage from roughing to finishing, and is a process of processing a processed sample by gradually decreasing the argon current density. In this way, the etching efficiency gradually decreases.

  The third step is a finishing step. In the third step, the argon current density is controlled so that most of the emitted ions are converted into atomic beams and the processing is performed with atomic beam irradiation. Then, when the electron current density reaches a predetermined value R, it is considered that a hole has been formed in the processed sample, the release of argon ions is stopped (finished the third step), and the processing is ended.

  In addition, symbols used below will be briefly described here. The constants determined by the designer are d, r, R, S, Δt and ΔT. As for dimensions, d is a dimensionless number, r, R and S are current densities, and Δt and ΔT are time. Further, the relations 0 <d <1, 0 <r <S / 2 <R <S, and Δt << ΔT are established. The measured value is the electron current density X. In addition, the argon current density Y is a value controlled by the microcomputer 30.

Further, it is assumed that the current density of electrons emitted from the electron gun is always kept at the value S. Further, this processing is such that U = 2V = S in the modification of claim 8 described in the means for solving the problem.
<First step>
When the ion gun control process is started, the microcomputer 30 first performs the first step. Specifically, the argon current density Y is set to a value S (S110). Next, the electron current density X is acquired from the current detector 40 (S120). Then, it is determined whether or not r ≦ X for the electron current density X acquired in S120 (S130). If it is determined that r ≦ X is not satisfied with respect to the electron current density X acquired in S120 (S130: No), the process returns to S120.
<Second step>
On the other hand, if it is determined that r ≦ X for the electron current density X acquired in S120 (S130: Yes), the microcomputer 30 proceeds to the second step. Specifically, first, the argon current density Y is set to be zero for a predetermined time Δt. That is, the release of argon ions is stopped. Then, the average value E (X) of the electron current density X during the period when the emission of argon ions is stopped is obtained from the current detector 40 (S140). Then, it is determined whether the average value E (X) acquired in S140 is S / 2 ≦ E (X) (S150).

  When it is determined that S / 2 ≦ E (X) is not satisfied with respect to E (X) acquired in S140 (S150: No), the argon current density Y is set to S−E (X) (S160), ΔT After elapses, the process returns to S150.

Incidentally, Δt and ΔT are sufficiently small values with respect to the time from the start to the end of processing. Further, specific examples of the average value E (X) acquired in S140 are represented as a value a and a value b in FIG.
<Third step>
On the other hand, if it is determined that S / 2 ≦ E (X) is obtained for E (X) acquired in S140 (S150: Yes), the process proceeds to the third step. Specifically, first, the value Y of the argon current density is set to E (X) * d (* is a multiplication symbol) for ΔT (S170). Then, when ΔT has elapsed since the start of S170, the emission of argon ions is stopped, and the average value E (X) of the electron current density X during that time is acquired from the current detector 40 (S180).

  Then, for E (X) acquired in S180, it is determined whether R ≦ E (X) is satisfied (S190). The value of R is slightly smaller than S. If it is determined that R ≦ E (X) is not satisfied for E (X) acquired in S180 (S190: No), the process returns to S170. On the other hand, when it is determined that R ≦ E (X) is obtained for E (X) acquired in S180 (S190: Yes), the argon current density Y is set to zero (S195), and the ion gun control process is ended.

  When the processed sample is processed by this ion gun control process, a graph as shown in FIG. 5 is obtained. FIG. 5 is a line graph showing the relationship between the argon current density Y and the electron current density X and the processing time. A thick line represents a change in the electron current density X, and a thin line represents a change in the argon current density Y.

  Further, as described in the means for solving the problem, d may be a variable. By the way, the purpose of using d as a variable is to ensure the processing by atomic beam irradiation instead of ion etching more reliably in the third step. In order to achieve this object, in the process of S170, the maximum value X ′ of the electron current density X in each process of S170 needs to satisfy the inequality X ′ <X * (1-d). In FIG. 5, each X ′ is represented as g1 to g4, and each X * (1-d) is represented as G1 to G4.

  This inequality will be described. If all the released argon ions combine with transmitted electrons and change to atomic beams, this inequality is always satisfied. On the contrary, the fact that this inequality is not satisfied indicates that there is a high possibility that argon ions are irradiated to the processed sample. Therefore, d in the processing of S170 may be a variable that takes the maximum value that satisfies this inequality.

  However, there is no theoretical basis that this inequality is satisfied even if d is changed. In that case, there is a possibility that the misalignment is not satisfied because the electron gun 10, the ion gun 20, and the holder 50 are misaligned.

  Therefore, in that case, the user may be warned that this inequality is not satisfied by an image display device or an audio output device (not shown) included in the microcomputer 30. Further, the electron gun 10, the ion gun 20, and the holder 50 are configured to include an actuator capable of adjusting their own alignment, and the microcomputer 30 controls the actuator so that this inequality is satisfied. May be.

  As described above, rough processing can be performed when the processed sample is thick, and the processing can be gradually shifted to thinning as the processing sample becomes thin, so that both shortening of processing time and clean finishing can be achieved.

  FIG. 6 shows a TEM integrated processing apparatus 200. Unlike the processing apparatus 1, the TEM integrated processing apparatus 200 includes an optical system as a TEM. With this configuration, the progress of processing can be confirmed by TEM at any time. In addition, observation can be performed immediately without transferring the thin film sample to another apparatus after processing.

  First, the components will be described. The TEM integrated processing apparatus 200 includes a case 205, an electron gun 210, an ion gun 220, a focusing lens 225 for an ion gun, a focusing lens 231, a shutter 290, a holder 250, an objective lens 233, a shutter 295, a projection lens 237, and a fluorescent plate 240. A CCD camera 243 and a monitor 246 are provided.

  From here, each component is demonstrated. First, the holder 250 is configured to be able to grip a processed sample, as in the first embodiment. The holder 250 is configured to be able to rotate the processed sample while holding the processed sample. Since this rotation mechanism is provided in an existing processing apparatus, it will be briefly described with reference to FIG.

  FIG. 7A is a top view showing details of the rotation mechanism of the holder 250 described above. The holder 250 includes a motor 251, a belt 253, a gear 255, and a rotary stage 257. In addition, the rotation mechanism is configured so that the rotation stage rotates in a range of −90 ° to 90 ° unlike the one described in the first embodiment.

  More specifically, the motor 251 is configured to rotate while changing the rotation direction so that the rotation stage 257 rotates in a range of −90 ° to 90 °, and to transmit the rotational motion to the belt 253. On the other hand, the belt 253 transmits the rotational motion to the gear 255. The rotary stage 257 that holds the processed sample is engaged with the gear 255, receives the rotational movement of the belt 253 via the gear 255, and rotates in a range of −90 ° to 90 °.

  FIG. 7B shows a state where the rotary stage 257 is −90 °, and FIG. 7C shows a state where the rotary stage 257 is 90 °. That is, the rotary stage 257 performs a rotational motion so as to change in the order of FIG. 7A → FIG. 7B → FIG. 7A → FIG. 7C → FIG.

  FIG. 7D is a diagram showing a BB cross section of the rotary stage 257. The rotation stage 257 is configured so that the rotation axis coincides with the center of the processed sample. By processing while rotating the processed sample in this way, processing can be performed without unevenness, and the finish becomes beautiful. Further, in this embodiment, the reason why the rotary stage is configured to rotate in the range of −90 ° to 90 ° is to adopt a known focused ion beam and process only the lateral half of the processed sample. is there.

  Further, the case 205 is configured to cover and seal the flight path of the electron beam and the focused ion beam, and the air pressure inside the case 205 is previously lowered. There are two purposes. One is to appropriately irradiate the processed sample with the electron beam emitted from the electron gun 210 and the focused ion beam emitted from the ion gun 220. The other is to make the fluorescent plate 240 appropriately emit fluorescence by the electron beam transmitted through the processed sample.

  Further, the ion gun 220 emits gallium ions as a focused ion beam toward a back surface of the processed sample from a predetermined angle. The ion gun focusing lens 225 focuses the emitted gallium ions toward the back surface of the processed sample. In this way, the back surface of the processed sample is processed.

  The electron gun 210 is a known field emission type used in a TEM or the like, and is configured to emit an electron beam and irradiate the surface of the processed sample held by the holder 250 with electrons.

  The focusing lens 231 is an electron lens provided between the electron gun 210 and the processed sample. The focusing lens 231 is configured so that the thickness direction of the processed sample held by the holder 250 and the traveling direction of the irradiated electrons are substantially parallel by focusing the electron beam toward the processed sample. ing. The objective lens 233 is provided between the focusing lens 231 and the projection lens 237 so as to cover both the front and back surfaces of the processed sample. Then, by generating a magnetic field in the electron beam path, the electron beam path is bent by the Lorentz force, and the electron beam is focused toward the processed sample.

  The projection lens 237 is an electronic lens provided between the processed sample and the fluorescent plate 240. That is, the electron beam that has passed through the processed sample is expanded toward the fluorescent plate 240 by the objective lens 233 and the projection lens 237. The fluorescent plate 240 forms a fluorescent image when the electron beam transmitted through the projection lens 237 is irradiated. In the TEM integrated processing apparatus 200 of this embodiment, this fluorescent image is captured by the CCD camera 243 and sent to the monitor 246 as image information. The monitor 246 displays the image information.

  The shutter 290 and the shutter 295 are existing and are made of beryllium, carbon, polyimide, or the like. That is, the shutter 290 and the shutter 295 are configured to transmit the electron beam while not transmitting the atoms.

  Specifically, the shutter 290 is provided between the focusing lens 231 and the objective lens 233, and partitions the upper layer space where the electron gun 210 is located from the middle layer space where the ion gun 220 and the holder 235 are located. It is configured to separate as a space. The shutter 295 is provided between the objective lens 233 and the projection lens 237, partitions the middle layer space where the ion gun 220 and the holder 235 are located, and the lower layer space where the fluorescent plate 240 is present, and separates them as independent spaces. It is configured. In this embodiment, by configuring the TEM integrated processing apparatus 200 in this way, a portion where the atmospheric pressure in the case 205 rises due to the release of gallium ions by the ion gun 220 is located between the shutters 290 and 295 (intermediate space). I try to stay at Thus, in this embodiment, the periphery of the electron gun 210 and the fluorescent plate 240 can be maintained at a pressure suitable for TEM observation.

  FIG. 8 shows a state in which a processed sample is processed by the TEM integrated processing apparatus 200. Fig.8 (a) is the figure which looked at the whole processing sample from the top, and MM (straight line which passes along the center of a circle) sectional drawing. Moreover, FIG.8 (b), FIG.8 (c), and FIG.8 (d) are the enlarged views of the center part vicinity of MM sectional drawing. Here, it is assumed that the processing proceeds in order from FIG. 8B to FIG. 8C and FIG. 8D.

  FIG. 8B shows a state when the processed sample is thick soon after the processing is started. In this state, electrons can hardly pass through the processed sample. That is, since the gallium ions and the electrons are hardly combined to change into an atomic beam, the atomic beam irradiation does not occur, and the etching efficiency does not deteriorate as in the conventional case.

  Then, as the processing progresses and the processed sample becomes thinner, the state as shown in FIG. In this state, the number of transmitted electrons gradually increases. However, when this state starts, the processed sample is thicker and needs to be processed thinner to observe with TEM. In this state, the transmitted electrons are combined with gallium ions to change the gallium ions into atomic beams. Due to this phenomenon, in this embodiment, the processing can be finished finely.

  Then, when the processing is further advanced, the state shown in FIG. In this state, the processed sample has a thickness suitable for observation by TEM, and the observation becomes possible. Then, it is confirmed using an optical system that observation is possible, and the processing is finished.

  As described above, in the processing apparatus according to the present embodiment, since the TEM optical system is provided in the apparatus, the operator operates the processing apparatus to process the processed sample, or performs processing. Immediately after completion, the thin film sample can be observed. Therefore, according to the present embodiment, the time from the start of processing to the observation can be shortened, which is convenient.

  In addition, according to the present embodiment, as in the processing apparatus of the first embodiment, electrons are irradiated on the surface of the processed sample and ions are irradiated on the back surface of the processed sample, so that both processing time is shortened and a clean finish is achieved. it can.

  Incidentally, the electron detector described in “Claims” corresponds to the fluorescent plate 240 described in the second embodiment. However, the electron detector is not limited to a fluorescent plate, and may be another optical device as long as an image of transmitted electrons can be observed. The ions emitted from the ion gun 20 and the ion gun 220 may be gallium ions or gallium ions or other rare gas atoms converted into cations. Other cations may be used as long as they do not hinder the use after processing. The purpose of processing may not be the production of a thin film sample for TEM observation.

1 is a diagram showing a schematic configuration of a processing apparatus 1 to which the present invention is applied. It is the top view (a) and AA sectional drawing (b) showing schematic structure of a holder rotation mechanism whose rotation range is -180 degrees-180 degrees. It is explanatory drawing showing the processing aspect of a sample. It is a flowchart showing an ion gun control process. It is a graph showing the relationship between the current density of a transmission electron, the current density of the ion which an ion gun discharge | releases, and processing time. It is a figure which shows schematic structure of the TEM integrated processing apparatus 200 to which this invention was applied. It is the top view (a) and BB sectional drawing (d) showing schematic structure of a holder rotation mechanism whose rotation range is -90 degrees-90 degrees. It is explanatory drawing showing the processing aspect of a sample.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Processing apparatus, 5 * 205 ... Case, 10 * 210 ... Electron gun, 20 * 220 ... Ion gun, 30 ... Microcomputer, 40 ... Current detector, 50 * 250 ... Holder, 51 * 251 ... Motor, 53 * 253 ... belt, 55/255 ... gear, 57/257 ... rotary stage, 200 ... TEM integrated processing device, 225 ... ion lens focusing lens, 231 ... focusing lens, 233 ... objective lens, 237 ... projection lens, 240 ... fluorescent plate 243 ... CCD camera, 246 ... monitor, 290/295 ... shutter

Claims (9)

A holder for gripping the workpiece;
An ion gun that emits predetermined cations and irradiates the work object gripped by the holder with the cations; and
An electron gun that emits electrons and irradiates the workpiece to be held by the holder with electrons;
A processing device for reducing the thickness, which is the distance between the front surface and the back surface of the processing object gripped by the holder,
The electron gun is arranged to be able to irradiate electrons on the surface of the workpiece,
The ion gun is arranged to be able to irradiate the cations on the back surface of the workpiece,
The back surface of the object to be processed is irradiated with the cation, the surface of the object to be processed is irradiated with electrons, and the thickness of the object to be processed held by the holder is reduced. Processing equipment. A current detector that irradiates the surface with the electron gun and measures the current density of electrons transmitted from the surface to the back surface;
A controller for controlling the current density of the cations emitted by the ion gun based on the measurement result of the current detector;
The processing apparatus according to claim 1, comprising: A holder for gripping the workpiece;
An ion gun that emits predetermined cations and irradiates the work object gripped by the holder with the cations; and
An electron gun that emits electrons and irradiates the workpiece to be held by the holder with electrons;
A processing device for reducing the thickness, which is the distance between the front surface and the back surface of the processing object gripped by the holder,
A processing apparatus comprising: an optical system that outputs, as image information, an image generated by electrons emitted from the electron gun and transmitted through the processing object. The electron gun is arranged to be able to irradiate electrons on the surface of the workpiece,
The ion gun is arranged to be able to irradiate the cations on the back surface of the workpiece,
The surface of the object to be processed is irradiated with electrons, the back surface of the object to be processed is irradiated with electrons, and the thickness of the object to be processed held by the holder is reduced. The processing apparatus according to claim 3. An electron detector that constitutes the optical system, configured to be able to detect electrons that are irradiated onto the surface of the workpiece by the electron gun and transmitted from the front surface to the back surface;
A case for sealing a space including an electron flight path from the electron gun to the electron detector so that atoms do not pass through;
A first shutter provided between the electron gun and the holder and partitioning a space in the case;
A second shutter provided between the holder and the electron detector and partitioning a space in the case;
With
5. The processing according to claim 3, wherein the first shutter and the second shutter are configured to transmit electrons emitted from the electron gun but not to transmit atoms. apparatus. The said ion gun discharge | releases what made the rare gas atom or the gallium atom the cation as said cation. The processing apparatus of Claim 1-5 characterized by the above-mentioned. The holder is configured to be capable of rotating the gripped workpiece about a rotation axis parallel to the thickness direction of the gripped workpiece. The processing apparatus as described in. A method for producing a thin film sample by producing a thin film sample by processing a workpiece and making it into a thin film,
By irradiating the surface of the object to be processed with electrons and irradiating the back surface of the sample to be processed, which is positioned symmetrically with the surface, with a predetermined cation, the surface and the back surface of the object to be processed A method of producing a thin film sample, wherein the thin film sample is produced by processing the sample to be processed so as to reduce the thickness, which is the distance of the thin film. The current density of electrons irradiated from the front surface of the sample to be processed and transmitted from the front surface to the back surface is measured, and based on the measurement result, the current density of the predetermined cation released is controlled. The method for producing a thin film sample according to claim 8, wherein the processing object is processed.

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